Polyamide resin compositions have found wide commercial acceptance because they can be formed into strong abrasion-resistant fibers and films. Those skilled in the art have endeavored to develop new types of polyamide resins which have improved dyeing properties, high impact strength, high tensile modulus, low temperature flexibility, thermal and chemical stability, and the like. Wholly aromatic polyamide resins exhibit improved thermal and chemical stability, but they have the disadvantage of being insoluble in common organic solvents, and their melting points are too high for convenient processing into useful articles by melting of the polymeric material.
Polyamide resin compositions tend to be susceptible to hydrolytic condtions and corrosive environments. The amido moieties in polyamide resin compositions are highly reactive and readily enter into chemical transformations. For example, in the production of polyamide block copolymer resins, it is a serious disadvantage that transamidation occurs, and the resultant resins have a random configuration rather than an authentic block copolymer structure.
Accordingly, it is an object of the present invention to provide polyamide resin compositions which have improved thermal and chemical stability.
It is another object of this invention to provide high molecular weight polyamide resin compositions which are soluble in ordinary solvents and can be conveniently converted into fibers, films and molded articles.
It is a further object of the present invention to provide a process for producing resinous linear polyamide block copolymers wherein transamidation between prepolymer reactants is suppressed.
Other objects and advantages shall become apparent from the following description and examples.